Process of producing alkali metals.



H. LABHARDT.

PROCESS 0F PRoDuclNG ALKALI METALS.

APPLICATION FILED DEC. I4, 1914- y l Patented July 1 8, 1916.

vw@ nto@ n Hansi-@Marcil @gl fClHozvlMg/J wwwa/som M2 JJM HANS LABHARDT, OF MANNHEIM, GERMANY, ASSIGNOB TO BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHIN E, GERMANY, A CORPORATION.

PROCESS OF PBODUCING ALKALI METALS.

meines.

Speci'cation of Letters Patent.

Application led December 14, 1914. Serial No. 877,099.

oir+oiif=ii2o+o giving rise to water and oxygen. This water rapidly diffuses through the electrolyte, the diffusion being assisted by the evolution of gas at the anode, and reacts with a part of the alkali metal which has been liberated at the cathode, so that a part of this alkali metal is reconverted into alkali hydroxid, and hydrogen is evolved according to the equation Consequently, the yield of alkali metal vis diminished.

I have found that I can obtain a much*A better yield of alkali metal during the elecf trolysis of molten alkali hydroxids ifI replace the alkali, which surroundsthe anode and has taken up Water,`by a fresh quantity of anhydrous caustic alkali. This replacement is preferably carried out continuously, so that a continuous currentof fresh anhydrous caustic alkali is supplied to the anode space while 'the alkali which contains water is run off and can be dehydrated and used over again.

This invention can be employed ,in the electrolysis of single alkali hydroxids, or of mixtures of alkali hydroxids.

The process according to this invention can be carried out, for example, in a cell the upper space ofwhich is separated by one,

or more than one, wall dipping slightly" into the electrolyte and dividing the said upper space into two, or more, spaces, one of which receives the products liberated at the cathode, namely alkali metal- "and hydrogen, while another serves as the anode space and collects the oxygen. The electrodes face one another in the electrolyte below the said separating Wall, or walls, and can, if desired, have a wire net interposed between them.` A pipe leading to the cell on the lcathode side serves for the introduction of dehydrated alkali, while another pipe, situated on the anode side is used for leading away alkali which has absorbed the water, so'v that the cell is traversed by a current of alkali 1n the direction from the cathode to the anode. In this way, the alkali which contains water is prevented, (or to a great degree prevented) from traversing from the anode to the cathode space. The current of alkali is regulated so that it is not' suflicienty to drag with it the rising drops of alkali metal, which metal collects yon the surface of the alkali in the cathode space and can be caused to run off continuously, or it can be hailed off from time to time.

Another example of a suitable way of carrying out the process according to this invention is to introduce the fresh anhy-4 drous alkali through an opening at the lower part of the cell and draw ofi the alkali which contains water from both the anode space and the cathodespace, the flow of alkali in. the two directions through the cell ,being regulated by means of valves, or

taps, situated in the pipes through which the alkali is led away from the cell.

The drawing accompanying this specification'is schematic and represents in verticalsect1on an apparatus suitable for car- 'rying out the process of my invention.

Patented July ie, wie.

In the drawing A represents the wall of the cell, B is the anode, C is the cathode and D is a 'wall dipping below the surface of the electrolyte and dividing the upper space into two parts. Oxygen is led away through the pipe E and any hydrogen which may be formed through the pipe F. Fresh molten alkali is passed into the cell through the pipe G, while alkali which has vabsorbed water at the anode passes away fromthe cell through the pipe H. The alkali metal which is formed is run off through the pipe K.

Now what I claim is 1. In the process of producing alkali metal by the electrolysis of molten caustic alkali, the step whichy consists in passing fresh anhydrous alkali into the cell and removing from the cell alkali which has absorbed water at the anode.

2. In the process of producing alkali metal by the electrolysis of molten caustic alkali, the step which consists in continuously passing fresh anhydrous alkali into the cell and continuously removing Vfrom the cell alkali Which has absorbed Water at the anode.

3. In the process of producing a mixture of sodium and potassium metal by electrolyzing a mixture of the hydroxids of said metals, the step which consists in continuously passing a fresh anhydrous molten lo mixture of the hydroxide into the cell and continuously removing from the cell a mixture of the hydroxids, Which has absorbed Water at the anode.

In testimony whereof I have hereunto set my hand in the presence 'of two subscribing 15 

